Real-Time BART In A Box Smaller Than Your Coffee Mug

November 11, 2025 by Matt Varian No comments

Ever get to the train station on time, find your platform, and then stare at the board showing your train is 20 minutes late? Bay Area Rapid Transit (BART) may run like clockwork most days, but a heads-up before you leave the house is always nice. That’s exactly what [filbot] built: a real-time arrival display that looks like it was stolen from the platform itself.

The mini replica nails the official vibe — distinctive red text glowing inside a sheet-metal-style enclosure. The case is 3D printed, painted, and dressed up with tiny stickers to match the real deal. For that signature red glow, [filbot] chose a 20×4 character OLED. Since the display wants 5 V logic, a tiny level-shifter sits alongside an ESP32-C6 that runs the show. A lightweight middleware API [filbot] wrote simplifies grabbing just the data he needs from the official BART API and pushes it to the little screen.

We love how much effort went into shrinking a full-size transit sign into a desk-friendly package that only shows the info you actually care about. If you’re looking for more of an overview, we’re quite fond of PCB metro maps as well.

Moving From Windows To FreeBSD As The Linux Chaos Alternative

November 11, 2025 by Maya Posch 15 Comments

Back in the innocent days of Windows 98 SE, I nearly switched to Linux on account of how satisfied I was with my Windows experience. This started with the Year of the Linux Desktop in 1999 that started with me purchasing a boxed copy of SuSE Linux and ended with me switching to Windows 2000. After this I continued tinkering with non-Windows OSes including QNX, BeOS, various BSDs, as well as Linux distributions that promised a ‘Windows-like’ desktop experience, such as Lindows.

Now that Windows 2000’s proud legacy has seen itself reduced to a rusting wreck resting on cinderblocks on Microsoft’s dying front lawn, the quiet discomfort that many Windows users have felt since Windows 7 was forcefully End-Of-Life-d has only increased. With it comes the uncomfortable notion that Windows as a viable desktop OS may be nearing its demise. Yet where to from here?

Although the recommendations from the peanut gallery seem to coalesce around Linux or Apple’s MacOS (formerly OS X), there are a few dissenting voices extolling the virtues of FreeBSD over both. There are definitely compelling reasons to pick FreeBSD over Linux, in addition to it being effectively MacOS’s cousin. Best of all is not having to deal with the Chaos Vortex that spawns whenever you dare to utter the question of ‘which Linux distro?’. Within the world of FreeBSD there is just FreeBSD, which makes for a remarkably coherent experience.

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Nest Thermostat: Now 100% Less Evil

November 11, 2025 by Al Williams 17 Comments

If you have a Nest thermostat of the first or second generation, you probably noticed it recently became dumber. Google decided to pull the plug on the servers that operate these devices, turning them into — well — ordinary thermostats. Lucky for us [codykociemba] has been keeping up with various exploits for hacking the thermostat, and he started the NoLongerEvil-Thermostat project.

If you want to smarten up your thermostat again, you’ll need a Linux computer or, with some extra work, a Mac. The thermostat has a DFU-enabled OMAP loader. To access it, you have to plug it into USB and then reboot it. There is a narrow window for the loader to grab it, so you have to be running the software before you reboot or you’ll miss it.

After that, the flash is relatively fast, but the Nest will look dead for a brief time. Then the No Longer Evil logo will show, and you are in business. We wish the hack simply replaced the Google software with a local website, but it doesn’t. It redirects all the network traffic to a custom URL. Then you can control your thermostat from the nolongerevil.com website. So we don’t know what will happen if they decide to stop hosting the remote server that powers this.

Then again, don’t look a gift horse in the mouth. If you get another year out of your trusty thermostat, that’s a year you wouldn’t have had otherwise. We do worry a bit about putting an odd device on your network. In theory, the project is open source, but all the important bits are in a binary U-Boot image file, so it would take some work to validate it. To get you started, the command to dump the content is probably: dumpimage -T kernel -p 0 -o kernel uImage. Or, you could watch it with Wireshark for a bit.

We were happy to get some more use out of our Nest.

Another Thermal Printer, Conquered

November 11, 2025 by Jenny List 6 Comments

The arrival of cheap thermal printer mechanisms over the last few years has led to a burst of printer hacking in our community, and we’re sure many of you will like us have one knocking around somewhere. There are a variety of different models on the market, and since they often appear in discount stores we frequently see new ones requiring their own reverse engineering effort. [Mel] has done some work on just such a model, the Core Innovation CTP-500, which can be found at Walmart.

The write-up is a tale of Bluetooth reverse engineering as much as it is one about the device itself, as he sniffs the protocol it uses, and finds inspiration from the work of others on similar peripherals. The resulting Python app can be found in his GitHub repository, and includes a TK GUI for ease of use. We like this work and since there’s an analogous printer from a European store sitting on the Hackaday bench as we write this, it’s likely we’ll be giving it a very close look.

Meanwhile if [Mel] sounds a little familiar it might be because of their print-in-place PCB holder we featured recently.

Photo of breadboards and bench oscilloscope

Programming The 6581 Sound Interface Device (SID) With The 6502

November 10, 2025 by John Elliot V 2 Comments

Over on YouTube, [Ben Eater] pursues that classic 8-bit sound. In this video, [Ben] integrates the MOS Technology 6581 Sound Interface Device (SID) with his homegrown 6502. The 6581 SID was famously used in the Commodore line of computers, perhaps most notably in the Commodore 64.

The 6581 SID supports three independent voices, each consisting of a tone oscillator/waveform generator, an envelope generator, and an amplitude modulator. These voices are combined into an output filter along with a volume control. [Ben] goes into detail concerning how to configure each of these voices using the available facilities on the available pins, referencing the datasheet for the details.

[Ben]’s video finishes with an 8-bit hit from all the way back in October 1985: Monty on the Run by Rob Hubbard. We first heard about [Ben’s] musical explorations back in June. If you missed it, be sure to check it out. It seems hard to imagine that demand for these chips has been strong for decades and shows little sign of subsiding.

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The Sanskrit Square Root Algorithm

November 10, 2025 by Al Williams 7 Comments

Years ago, no math education was complete without understanding how to compute a square root. Today, you are probably just reaching for a calculator, or if you are writing a program, you’ll probably just guess and iterate. [MindYourDecisions] was curious how people did square roots before they had such aids. Don’t remember? Never learned? Watch the video below and learn a new skill.

The process is straightforward, but if you are a product of a traditional math education, you might find his terminology a bit confusing. He will refer to something like 18b meaning “a three-digit number where the last digit is b,” not “18 times b,” as you might expect.

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A photo of [nanofix]'s bench including his FNIRSI soldering station.

Investigating Soldering Iron Phantom Voltage

November 10, 2025 by John Elliot V 12 Comments

Just because you are paranoid doesn’t mean people aren’t out to get you. Do you think your soldering iron is after you? Well, [nanofix] asks (and answers): Is My Soldering Iron Dangerous?

He has a look at his cheap FNIRSI soldering station and measures a “phantom voltage” of nearly 50 volts AC across the tip of his iron and earth ground. He explains that this phantom voltage is a very weak power source able to provide only negligible measures of current; indeed, he measures the short circuit current as 0.041 milliamps, or 41 microamps, which is negligible and certainly not damaging to people or components.

He pops open his soldering iron power supply (being careful to discharge the high voltage capacitor) and has a look at the switched mode power supply, with a close look at the optocoupler and Y-class capacitor, which bridge the high voltage and low voltage sides of the circuit board. The Y-class capacitor is a special type of safety capacitor designed to fail open rather than fail short. The Y-class capacitor is there to remove high-frequency noise. Indeed, it is this capacitor that is the cause of the phantom voltage on the iron tip.

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